An inkjet recording apparatus includes a heater and a recording head. The heater is disposed upstream of the recording head in terms of a conveyance direction of a recording medium. The recording medium heated by the heater has a temperature of from 40 to 80° C. The ink contains a pigment, a cellulose derivative, first and second water-soluble organic solvents, and water. The first water-soluble organic solvent is glycol ether. The second water-soluble organic solvent is a water-soluble organic solvent that is not glycol ether. The cellulose derivative has a percentage content of from 0.01 to 0.20% by mass relative to the mass of the ink. The percentage content of the glycol ether is from 6 to 24% by mass relative to the mass of the ink and from 20 to 80% by mass relative to the total mass of the first water-soluble organic solvent and the second water-soluble organic solvent.

An inkjet recording apparatus includes a heater and a recording head. The heater is disposed upstream of the recording head in terms of a conveyance direction of a recording medium. The recording medium heated by the heater has a temperature of from 40 to 80° C. The ink contains a pigment, a cellulose derivative, first and second water-soluble organic solvents, and water. The first water-soluble organic solvent is glycol ether. The second water-soluble organic solvent is a water-soluble organic solvent that is not glycol ether. The cellulose derivative has a percentage content of from 0.01 to 0.20% by mass relative to the mass of the ink. The percentage content of the glycol ether is from 6 to 24% by mass relative to the mass of the ink and from 20 to 80% by mass relative to the total mass of the first water-soluble organic solvent and the second water-soluble organic solvent.

An element substrate, according to an embodiment of this present invention, capable of detecting the behavior of a liquid at a high sensitivity, comprises: a first electrothermal transducer configured to generate heat to discharge a liquid; at least one temperature detection element arranged near the first electrothermal transducer; and a second electrothermal transducer configured to generate heat in association with a temperature detection operation by the at least one temperature detection element.

An element substrate, according to an embodiment of this present invention, capable of detecting the behavior of a liquid at a high sensitivity, comprises: a first electrothermal transducer configured to generate heat to discharge a liquid; at least one temperature detection element arranged near the first electrothermal transducer; and a second electrothermal transducer configured to generate heat in association with a temperature detection operation by the at least one temperature detection element.

An ink-jet ink composition includes: a solvent; a pigment comprising a first powder, the surface of which, in the solvent, bears a first charge; an ionic polymer having a second charge, which is counter to the first charge; and polyvalent ions having the first charge. The ink composition has a surface tension of 53 mN/m or less.

An ink-jet ink composition includes: a solvent; a pigment comprising a first powder, the surface of which, in the solvent, bears a first charge; an ionic polymer having a second charge, which is counter to the first charge; and polyvalent ions having the first charge. The ink composition has a surface tension of 53 mN/m or less.

A print element substrate, comprising a plurality of heating elements, a plurality of detection elements, each configured to detect a temperature of a corresponding heating element, a first current generation unit, a second current generation unit, and a signal output unit, wherein one of the first and second current generation units supplies a current to a first detection element, the other supplies a current to a second detection element, and the signal output unit outputs a signal according to a potential difference between one terminal of the first detection element on a side where a potential variation occurs upon supply of the current and one terminal of the second detection element on a side where a potential variation occurs upon supply of the current.

A print element substrate, comprising a plurality of heating elements, a plurality of detection elements, each configured to detect a temperature of a corresponding heating element, a first current generation unit, a second current generation unit, and a signal output unit, wherein one of the first and second current generation units supplies a current to a first detection element, the other supplies a current to a second detection element, and the signal output unit outputs a signal according to a potential difference between one terminal of the first detection element on a side where a potential variation occurs upon supply of the current and one terminal of the second detection element on a side where a potential variation occurs upon supply of the current.

A fluid-ejection element of a fluid-ejection device includes a chamber layer having a pair of chambers fluidically disconnected from one another within the chamber layer. The fluid-ejection element includes a tophat layer over the chamber layer and fluidically connecting the chambers to define a fluid recirculation path between the chambers. The fluid-ejection element includes a nozzle common to both the chambers.

A liquid discharge head substrate, comprising a discharging element configured to discharge a liquid, a driver configured to drive the discharging element, a conductive protection film covering the discharging element via an insulating film, and a controller connected to the protection film and configured to output a control signal that sets the driver in an inactive state when a change of a voltage of the protection film or a change in a current that flows to the protection film is detected.